Two teams of scientists have found the weeds are cross-breeding with genetically modified crops, making them nearly impossible to kill with pesticides.

Increasingly in order to be competitive, lamb on the butcher's slab comes from sheep cross-bred for size and fast weight gain, kept partially indoors and fed concentrates, thus ready for market at 13 weeks.

They are in demand for cross-breeding with Thoroughbreds to produce 3-day eventers (dressage, field jumping, show jumping), jumpers and dressage horses.